The present invention relates to welding apparatus, and in particular to an apparatus for welding metal grating structures.
Metal gratings of the type comprised of intersecting elements defining interstices therebetween find use in landings, walkways, platforms, trench covers and stair treads. Depending upon the particular use for which the grating is intended, the same is often provided with additional structural components. For example, if the grating is to be used to cover a trench, banding bars may be welded along side edges of the grating to facilitate handling and to form closed edges thereof for smoothly abutting a frame in which the grating is placed. In the case where the grating is used in a stair tread, a nosing having a roughened surface is usually affixed to a leading edge of the grating to provide a non-slip safety surface, and if the stair tread is to be mounted along or between adjacent walls or other supports, end plates may be affixed to side edges of the grating to facilitate its mounting.
The various components which may be affixed to the grating are of metal, and are most expeditiously attached to the grating by welding. Conventionally, this comprises placing the grating and components on a fixture for holding the same in aligned relationship, and then welding the parts together, all by manual operation. Such a method of assembly is quite slow and therefore expensive, particularly in the manufacture of stair treads in which four parts, a grating, nosing and two side plates are joined.